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Eingeladener Vortrag
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A controlled, reproducible, gram-scale method is reported for the covalent functionalization of graphene Sheets by a one-pot nitrene [2+1] cycloaddition reaction under mild conditions. The reaction between commercially available 2,4,6-trichloro-1,3,5-triazine and sodium azide with thermally reduced graphene oxide (TRGO) results in defined dichlorotriazine-functionalized sheets. The different reactivities of the chlorine substituents on the functionalized graphene allow stepwise post-modification by manipulating the temperature.
This new method provides unique access to defined bifunctional 2D nanomaterials, as exemplified by chiral surfaces and multifunctional hybrid architectures.
The use of duplex stainless steels (DSS) in energy related applications is well known. Nowadays, DSS steels become more favorable than austenitic steels due to the outstanding mechanical properties, the good corrosion resistance and the lower nickel content. However, the use of the duplex grade in acidic environments such as seawater often leads to severe degradation of the structural integrity of the steel by hydrogen-induced/assisted cracking (HAC) phenomena, which can eventually result in premature failure. Hydrogen assisted degradation and cracking of steels are active fields of research even though this topic is intensively studied for more than a century. A bottleneck is the analytical validation of the theoretical models proposed ion the literature at the sub-micron scale.
Industrial and the research communities see a need for an accurate analytical method by which it is possible to image the distribution of hydrogen in the microstructure of a steels or and other alloys. Among the very few available methods hydrogen imaging methods, Time-of-Flight secondary ion mass spectrometry (ToF-SIMS) has the principal capability for mapping of hydrogen in a steel’s microstructure. The combination of ToF-SIMS with multivariate data analysis (MVA), electron microscopy (SEM) and electron-backscattered diffraction (EBSD) is a powerful approach for providing chemical and structural information. The use of data fusion techniques has been shown recently to enhance the better understanding of the hydrogen induced degradation processes in in a DSS steel.
CCQM has established a framework of comparisons to demonstrate the international comparability of chemical measurements. The key point is the establishment of comparable measurements, with traceability to internationally or nationally stated references.
Originally initiated by Dr Martin P Seah, NPL, the Surface Analysis Working Group (SAWG) has been formally founded in 2003. The following terms of reference were presented to CCQM in April 2002. CCQM ratified the group as a full working group of CCQM in April 2003 with these terms of reference:
- to develop pilot studies and carry out key comparisons of national measurement standards for surface and micro/nano-analysis;
- to assist in identifying and establishing inter-laboratory work to improve the traceability of surface and micro/nano-analysis;
- to establish and update a work plan to be adopted by CCQM;
- to discuss and review the scope of the working group and to liase with other working groups related to nanotechnology.
Following the 2016 meeting, the Key Comparison K-129 "Measurement of atomic fractions in Cu(In,Ga)Se2 Films" lead by KRISS and the Key Comparison K-136 on "BET specific surface area of nanoporous Al2O3" lead by UNIIM&BAM have been finished in 2016.
The 15th meeting of SAWG will focus on
- survey on CMC claim submitted with reference to K-129 and K-136.
- the overall and SAWG specific aspects of the CCQM Strategy process,
- a joint meeting with the Inorganic Working Group addressing number concentrations of nano particles,
- discussion of future comparisons.
An electron effective attenuation length (EAL) of 1.68nm for Al Kα excited Pd 3d 5/2 photoelectrons with a kinetic energy of 1.152 keV has been determined experimentally using a sputtered Pd film deposited on an ultra flat fused quartz substrate. The film thickness was reduced by Ar ion sputtering several times in order to obtain different Pd film thicknesses which are used to determine experimental EAL values. These results are compared to data generated by using a Simulation of Electron Spectra for Surface Analysis (SESSA) simulation using an inelastic mean free path (IMFP) calculated with the Tanuma–Powell–Penn (TPP)-2M formula and with ‘elastic scattering on and off’. Contributions to the uncertainty budget related to the experimental approach are discussed in detail. Proposals on how to further improve the approach are suggested.
ISO/TR 19693:2018—Surface chemical analysis—Characterization of functional glass substrates for biosensing applications gives an overview of methods, strategies, and guidance to identify possible sources of problems related to substrates, device production steps (cleaning, activation, and chemical modification), and shelf life (storage conditions and aging). It is particularly relevant for surface chemical analysts characterizing glass‐based biosensors, and developers or quality managers in the biosensing device production community. Based on quantitative and qualitative surface chemical analysis, strategies for identifying the cause of poor Performance during device manufacturing can be developed and implemented. A review of measurement capabilities of surface analytical methods is given to assist readers from the biosensing community.
The international ISO Standard 20579‐4, dealing with the history and preparation of nano‐objects for surface analysis, has been developed to help address some of the replication and reproducibility issues caused by the fundamental nature of nanoobjects.
Although all types of samples requiring surface analysis need thoughtful preparation, nano‐objects, for which many properties are controlled by their surfaces, present additional challenges in order to avoid variations and artefacts due to the handling and preparation of materials prior to analysis. This international standard is part of a series of standards related to preparation of samples for surface chemical analysis. Parts 1 and 2 of ISO Standard series 20579 address general issues that apply to many samples. Part 3, which is still in development, will focus on biomaterials. Part 4 specifically considers issues that arise due to the inherent nature of nano‐objects.
Because of sensitivity to their environment, the standard indicates the minimum Information that needs to be reported about the handling and preparation of nano‐objects prior to surface analysis. This information should become part of sample provenance information that helps assure the reliability and usefulness of data obtained from surface‐analysis in the context of the synthesis, processing, and analysis history of a batch of material. Application of this standard can help address reproducibility and traceability issues associated with synthesis, processing, and characterization of nano‐objects in research and commercial applications.
The effect of electrochemical charging of hydrogen on the structure of a lean duplex stainless steel LDX 2101® (EN 1.4162, UNS S32101) was examined by both Time-of-Flight secondary ion mass spectrometry and electron back-scatter diffraction. The goal is to correlate hydrogen concentration and induced structural changes. Chemical and structural characterizations were done for the same region at the sample's surface with sub-micron spatial resolution. Regions of interest were varying in size between 50 × 50 μm and 100 × 100 μm. The results show a phase transformation of austenite to mainly a defect-rich BCC and scarcely a HCP phase. The phase transformation occurred in deuterium rich regions in the austenite.
Graphene is a two-dimensional carbon network with unique properties, including high mechanical stiffness, strength, and elasticity, outstanding electrical and thermal conductivity, and many others. Despite these advantages, its low solubility, poor reactivity and the limited accessibility of a well-defined basal plane are major challenges for applications. An ideal method to overcome these problems is the covalent attachment of functional molecules to its surface which enables further reactive modifications for specific applications. There is a number of different technologies for surface functionalization of graphene and related CNT materials. However, to get control on the functionalization process and to optimize the performance of the modified surfaces analytical tools for surface chemical characterization are required. X-ray absorption (NEXAFS) and photoelectron spectroscopy (XPS) have been identified to be rather powerful here. Specifically NEXAFS spectroscopy underpinned by quantum chemical spectrum simulations is unique in a way to address changes of aromaticity and defect formation at the graphene surface during functionalization.
For relevant surface modification technologies, we present examples on how NEXAFS and XPS can perform well. All presented modifications aim on the production of platforms for defined functional 2D nanomaterials, as for example multifunctional hybrid architectures. In detail, we investigated:
• Graphene and carbon nanotube functionalized by a Vacuum-Ultraviolet (VUV) induced photochemical process in NH3 or O2 atmospheres in order to introduce amino or hydroxy functionalities, respectively.
• Br bonding on r.f. cw low pressure plasma brominated graphite surfaces by using Br2 and bromoform as plasma gases.
• A wet chemical method for covalent functionalization of graphene sheets by a one-pot nitrene [2+1] cycloaddition reaction under mild conditions. Here a reaction between 2,4,6-trichloro-1,3,5-triazine and sodium azide with thermally reduced graphene oxide (TRGO) results in defined dichlorotriazine-functionalized graphene sheets.
A central challenge to ensure the sustainable production and use of nanotechnologies is to understand the risks for environment, health and safety associated with this technology and resulting materials and products, and to identify and implement practical strategies to minimize these risks. Knowledge about nanotechnology-enabled processes and products and related environment, health and safety issues is growing rapidly, achieved through numerous European or national R&D programs over the last decade, but effective use of this knowledge for risk management by market actors is lagging behind.
The EC4SafeNano initiative (www.EC4SafeNano.eu) is an ongoing effort to build a European Centre for Risk Management and Safe Innovation in Nanomaterials and Nanotechnologies. EC4SafeNano aims to bridge the gap between scientific knowledge on hazard and risk, and ‘fit-for-purpose’ risk management tools and strategies supported by measurement and control methods. The consortium comprises 15 partners (INERIS (coordinator), EU-VRi, TNO, BAM, FIOH, VITO, SP, DEMOKRITOS, TECNALIA, Health and Safety Executive, NRCWE, Paris Lodron University Salzburg, Université Libre de Bruxelles, University of Birmingham and ENEA) from 11 European Member States with significant expertise on risk assessment and management, who already provide knowledge and technical services to public and private organizations, to industry and to public authorities and regulatory bodies.
The overall objective of the EC4SafeNano project is to develop a distributed Centre of European Organisations offering services for Risk Management and Safe Innovation for Nanomaterials & Nanotechnologies. The Centre will be structured as a hub-based network of organizations managed by a core group of public-oriented bodies providing risk management and safe innovation support to all stakeholders. It will be operated with the support of Associated Partners so as to expand its capabilities, resources and services. It will interact with existing platforms and centres of excellence in nanosafety and foster the organization or development of national hubs mirroring the European hub. The Centre will seek financial support from stakeholders and service users to sustain the services in the longer term.
The operational objectives of the project involve understanding and mapping the needs of the various stakeholders (private and public). It will identify the resources and capabilities and develop a range of harmonized services required to meet these needs. The construction of the centre will include putting in place and implementing processes to deliver and update services, to test and benchmark services, to evaluate the governance of the Centre, and developing a business plan to ensure self-sufficiency of the Centre beyond the project lifetime.
A cornerstone of the project is to build a community for risk management and safe innovation for nanotechnology. Interested persons or organisations are invited to join this initiative as registered stakeholders or Associated Partners, to engage in focus networks and to help shape the future Centre. The poster will present the EC4SafeNano initiative and will detail the role of registered stakeholders and Associated Partners.
Die Präsentation gibt einen Überblick über die verschiedenen Aktivitäten der BAM im Bereich der Nanotechnologie mit den Schwerpunkten Nanopartikel und Nanosicherheit. Es wird sowohl die Transportsicherheit, als auch die Sicherheit von Batterien mit Nanopartikeln angesprochen. Verschiedene BAM-Projekte zum Thema Nano werden vorgestellt, beginnend mit relevanten REFOPlanprojekten über die Erstellung der OECD nanoTG110 bis hin zu EU-Projekten zur Standardisierung von Messungen an Nanomaterialien, hier insbesondere AEROMET, NanoDefine, NanoValid und EC4SafeNano.